Labour MP Debbie Abrahams a member of the work and pensions committee that is conducting the inquiry, told McVey there was “an increasing… and a worrying number of deaths that are being associated with sanctions”.

Abrahams asked McVey how many of the peer reviews concluded that the deaths had been associated with the use of benefit sanctions.

McVey said it was “wrong” of Abrahams to “politicise” and “inflame” the issue, and refused to answer her question.

But when Abrahams asked civil servant Chris Hayes, DWP’s labour market strategy director, whether any of the 49 peer reviews had found DWP’s actions to have been “inappropriate or incorrect”, he said he would “have to look at the peer reviews in detail” in order to answer her question.

He came closest to suggesting that some of the reviews had attached some blame to the government when he added: “We have found no particular case where as a direct result of sanctions alone, that has led to someone being in that situation.”

But when DNS asked a DWP spokeswoman to clarify whether Hayes had committed to looking at the reviews in detail, she said: “My understanding was there was no commitment. He didn’t commit to looking at the detail.”

Asked whether she had actually asked Hayes to clarify his remarks, she said: “I am not going to tell you how I have dealt with your enquiry.”

The session had begun with the committee’s chair, the disabled Labour MP Dame Anne Begg, repeatedly asking whether the government had any evidence to justify its decision to introduce a stricter sanctions regime through the Welfare Reform Act 2012.

The act brought in tougher regimes for claimants of both employment and support allowance and jobseeker’s allowance (JSA), with the minimum JSA sanction increasing from two to four weeks without benefits, and the maximum sanction from six months to three years.

Dame Anne repeatedly asked what evidence the government had possessed at the time on the impact of extending these sanctions on individual claimants without money, but McVey avoided answering the question.

Dame Anne told her: “There is a group of people as a result of the toughening of the sanction regime left destitute because the system is not working.”

Her Labour colleague Glenda Jackson told McVey: “You have introduced punitive sanctions and you have given absolutely no evidence so far this morning that that is effective in getting people into work.

“What we have had evidence of is, because of sanctions, people simply no longer go into Jobcentre Plus and as far as we are aware they have completely fallen off the system.”

But the disabled Conservative committee member Paul Maynard said the sanctions regime under the previous Labour government had also been “punitive” and had “trapped” claimants with a literacy or numeracy problem or a learning difficulty.

He said Labour’s system was “more cruel because it left far more on the scrap-heap”, while the current system was more personalised.

Abrahams also told McVey that it was a “nonsense” that ministers had said they could no longer produce figures to show how much money in total had been taken from claimants through sanctions.

Government figures had previously estimated that £45 million had been taken in 2010-11, and £60 million in 2011-12, compared with just £11 million in 2009-10, in the last year of the Labour government.

But McVey said DWP no longer published any figures because there were too many “caveats” to produce anything meaningful.

Abrahams said independent research – carried out by Dr David Webster of the University of Glasgow’s urban studies department – had estimated that the amount lost by JSA claimants had risen to £275 million a year*, although McVey said she did not recognise this figure.

*Disability News Service has confirmed with Dr Webster that this estimated figure refers to the net amount lost to claimants through JSA sanctions (money lost through having benefits stopped minus any hardship payments received by the claimant) from July 2013 to June 2014